TB67S279FTG TB67S289FTG TB67S249FTG Usage considerations

Transcription

1 TB67S279FTG TB67S289FTG TB67S249FTG Usage considerations Main Specifications Product number Control I/F Absolute maximum ratings Package TB67S279FTG / TB67S289FTG / TB67S249FTG CLOCK-IN 50 V, 2 A (TB67S279FTG), 3 A (TB67S289FTG), 4.5 A (TB67S249FTG) QFN48 Step resolution Other features Full, Half (a)/(b), Quarter, 1/8, 1/16, and 1/32 step resolution Adoption of AGC, ADMD, and ACDS architectures Built-in error detection functions (thermal shutdown, over current protection, under voltage lock out, and motor load open detection) Built-in error detection signal output function Support the power-on sequence by the single power drive Automation oscillation circuit which does not require components Please take utmost care in handling of this document because product information etc., are included. (It is only for the relevant divisions in your company.) Moreover, the technical information including IC characteristics in this document is preliminary and may be changed without notice. Please contact us about the newest information accordingly. (Version of March 7, 2018) Toshiba Electronic Devices & Storage Corporation 1 / 33

2 1. Outline of IC TB67S279FTG, TB67S289FTG, and TB67S249FTG can control a single 2-phase bipolar stepping motor. This IC supports from 12 V to 42 V power supply and large-current drive for motors by adopting 50 V monolithic analog process (BiCD: Bipolar CMOS DMOS). The specification differences between TB67S279FTG, TB67S289FTG, and TB67S289FTG are output capabilities (capabilities of Ron and Iout), Gain (VREF (gain)) that determines the constant current rating, and over current detection (ISD) threshold. Pin assignments are same. CLK-In Decoder for micro stepping drive is incorporated, allowing motors to drive with sine-wave current by inputting CLK signals. It realizes fast and accurate current following with ADMD (Advanced Mixed Decay Mode). Also, external components can be eliminated by adopting ACDS (Advanced Current Detection System) and the component-elimination mode of the internal oscillation circuit. The greatest feature of the IC is adopting AGC (Active Gain Control: anti-stall function) technology. It can achieve high efficient motor drive, while preventing motor stalls. Usage methods and notes in using the IC are described from the next section. 2. Power Supply Voltage 2.1. Power supply voltage and operation range In using TB67S279FTG, TB67S289FTG, and TB67S249FTG, the voltage should be applied to the pins of VM (VMA, VMB) and VREF (VREFA, VREFB). Built-in VCC regulator for internal logic power supply enables the IC to operate with a single power supply. Applying an external voltage is unnecessary. The maximum rating of the motor supply voltage is 50 V. Its operation voltage range is 10 V to 47 V. The maximum voltage rating, which is applied to VREF pin for PWM threshold, is 5 V. Its operation range is 0 to 3.6 V. VREF is configured by voltage of VCC regulator and can be set by dividing voltage in necessary. However, if the current value exceeds the capability of the VCC regulator, the output voltage may not be kept. Therefore, when VREF is applied by dividing VCC, the voltage-dividing resistance (combined resistance of VCC and GND) should be in the range of 10 kω to 100 kω. Table 2.1 Operation ranges of power supply voltage (Ta=-20 to 85 C) Item Symbol Absolute maximum ratings Operation range Unit Remarks Motor power supply voltage VM to 47 V Setting voltage for PWM threshold VREF to 3.6 V Voltage for internal logic power supply VCC to 5.25 V Supplied by internal regulator 2 / 33

3 3. Power Supply Sequence There are no special procedures between power sources in powering on and shutdown because TB67S279FTG, TB67S289FTG, and TB67S249FTG can operate with a single power supply by the VCC regulator. Moreover, built-in under voltage detections (UVLO and power on reset function (POR)) avoid malfunction, which occurs at the UVLO/POR detection threshold or less. While POR is activated, the internal logic is initialized. The UVLO/POR detection threshold is as follows; in startup = 7.5 V±1.0 V, in shutdown = 7.0 V±1.0 V, and the hysteresis = 0.5 V (typ.). Motor power supply voltage (VM) 8.5 V 7.5 V 6.5 V 8.0 V 7.0 V 6.0 V VMPOR (H): 7.5 V ± 1.0 V VMPOR (L): 7.0 V ± 1.0 V Figure 3.1 Power supply voltage and operation range 3 / 33

4 4. Output Current Output current value for the motor depends on the power consumption that refers to the voltage drop at the on resistance of the output circuit. From the above, the absolute maximum current rating of each IC is as follows; 2 A (TB67S279FTG), 3 A (TB67S289FTG), and 4.5 A (TBS249FTG). These ratings must not be exceeded, even for a moment. The actual-usage maximum current is limited depending on the usage conditions (the ambient temperature, the wiring pattern of the board, the radiation path, the exciting design, etc.). Therefore, configure the most appropriate current value after calculating the heat and evaluating the board under the operating environment. Moreover, the IC drives the motor with a constant-current control by ACDS technology. Recommended lower current limit for appropriate motor operation is as follows; TB67S279FTG: 0.5 to 1.0 A, TB67S289FTG: 1.0 to 1.5 A, and TB67S249FTG: 1.5 to 2.0 A. When the configured current is too small in using large-current drive devices, malfunctions such as offset may occur. 5. Control Logic Input The IC can avoid malfunction occurred by the electromotive force, which generates when the control logic signal is input without VM voltage. However, it is recommended to set the control logic signal low level while VM is not supplied. Configure the control logic signal low level during powering on and shutdown (refer to 2.1 Power supply voltage and operation range ) and input the operation signal after VM and VREF reach the operation voltage range. 6. PWM Control 6.1. Setting PWM threshold TB67S279FTG, TB67S289FTG, and TB67S249FTG can configure the constant current PWM threshold only by the applied voltage to the VREF pin. External current detection resistor is not required. (ACDS technology) The current value (Iout) of TB67S279FTG, TB67S289FTG, and TB67S249FTG can be approximated from below formulas. Iout = VREF (TB67S279FTG) Iout = VREF (TB67S289FTG) Iout = VREF (TB67S249FTG) VREF gain of each IC is as follows; TB67S279FTG: (typ.) TB67S289FTG: (typ.) TB67S249FTG: 1.25 (typ.) Then, when the voltage of 2 V is input to VREF pin in using TB67S289FTG, setting current is as follows; Iout = 2 V = 1.67 A (typ.) 4 / 33

5 6.2. Setting internal oscillation frequency (foscm) and constant current PWM (chopping) frequency (fchop) TB67S279FTG, TB67S289FTG, and TB67S249FTG can set the internal oscillation frequency (foscm) and the PWM (chopping) frequency (fchop) with the constant numbers of the external components (resistor and capacitor), which are connected to OSCM pin. The internal oscillation frequency can be set by connecting the resistor (ROSC) between VCC and OSCM pin, and connecting the capacitor (COSC) between OSCM pin and GND. Please set it by changing the ROSC value, while fixing the COSC value to 270 pf. The relational expression of the internal oscillation frequency (foscm) and the external resistance (ROSC) is as follows (COSC = 270 pf); foscm = 4.0 ROSC -0.8 Note: Unit: foscm (MHz) and ROSC (kω) Refer to the following graph for the relation of the external component and the measured data of the internal oscillation frequency (reference data). The relational expression of the internal oscillation frequency (foscm) and the constant current PWM (chopping) frequency (fchop) is as follows; fchop = foscm / 16 OSCM oscillation waveform Internal OSCM oscillation waveform Operation is controlled with constant current by applying 16 counts of the internal OSCM oscillation waveform as one cycle. (It can be monitored by OSCM pin. Waveform inclination changes depending on the external component.) (OSCM oscillation frequency waveform is fabricated to the rectangle waveform by comparing to the reference data. It cannot be monitored by external devices.) Figure 6.1 Relation of OSCM pin oscillation waveform and internal OSCM oscillation waveform 5 / 33

6 Function of internal oscillation circuit: Elimination of external components The internal oscillation circuit of TB67S279FTG, TB67S289FTG, and TB67S249FTG has the function of eliminating external components. As mentioned previously, the oscillation frequency can be changed arbitrarily by connecting external components (resistor and capacitor) to the OSCM pin and adjusting their constant numbers. Also, the motor can be controlled by internal fixed frequency without using external components. When using this function, remove both resistor and capacitor and connect the OSCM pin to the GND. When the IC recognizes that the OSCM pin is short-circuited, the internal oscillation circuit switches to use the external-component eliminating mode. In this mode, configuration of the internal oscillation frequency (foscm) is about 930 khz and of the constant current PWM (chopping) frequency (fchop) is about 60 khz that is 1/16 of foscm Notes in using the component-elimination drive function of the OSCM pin This function is activated when judging period of 20 μs (typ.) has passed after both POR and STANDBY are released. If the signal is input during this judging period, it may not be reflected correctly. Therefore, do not input control signals during this period. Moreover, while the motor is operating, be sure to fix OSCM mode to either the normal drive mode or the external-component elimination mode. Switching the OSCM mode during motor operation is prohibited. 6 / 33

7 6.3. Constant current waveform when chopping frequency changes Chopping frequency (fchop) is recommended to set about 67 khz in using the IC. When the chopping frequency is increased, ripple current of the motor is decreased and the waveform quality is improved. However, the heat generates because the increased chopping frequency enhances the switching loss. To improve the waveform quality, increase the chopping frequency. To reduce the heat generation, decrease the frequency. Example 1: When chopping frequency (fchop) = 100 khz, Step following capability is fast. Set current value Set current value NF Fast Charge Charge NF NF Fast Fast Charge Slow NF Charge Fast Slow Slow fchop = 100 khz fchop = 100 khz fchop = 100 khz fchop = 100 khz The number of chopping is large (Switching loss and heat are large) Figure 6.2 Chopping frequency (100 khz) Example 2: When chopping frequency (fchop) = 72 khz, Set current value Step following capability is slow. NF Fast Set current value NF Charge Fast Charge Slow Slow fchop = 72 khz fchop = 72 khz The number of chopping is small (Switching loss and heat are small) Figure 6.3 Chopping frequency (72 khz) Generally, it is recommended to use the IC with the frequency range of 50 khz to 120 khz based on 67 khz as a typical value. 7 / 33

8 7. Output Switching Characteristics 90% 90% 10% 10% tr tf Figure 7.1 Switching characteristics Table 7.1 Switching characteristics Ta = 25 C, VM = 24 V, No load (Example of TB67S249FTG) Item Typ. Unit tr 80 ns tf 90 ns Note: Confirm the electrical characteristics of the data sheet for each value. 8 / 33

9 8. Function Explanation This chapter describes the basic functions of stepping motors CLK function An electrical angle advances one unit according to the driving mode, which is configured by each pulse of CLK signal. Each signal is reflected at upper edge of CLK signal. The analog filter of 200 ns (±20%) is implemented for CLK pin to avoid malfunction due to noise. Duty of CLK signal is not necessary to set 50 %. However, pay attention to configure the maximum frequency of the CLK signal in considering this analog filter of 200 ns. When the state of inputting upper edge signal continues due to noise, upper edge signal is reflected after the filtering period. In this case, the motor may stall because the electrical angle advances according to the below function regardless of the signal reflecting state. Pay attention to design the wiring layout for CLK pin not to be influenced by noise. CLK Upper edge Down edge Function Shifts the electrical angle and current step per each upper edge. (no change, maintain former state) 8.2. ENABLE function This function switches ON and OFF of the output circuit of the IC. Motor operation (i.e., current outputting) starts when this function is enabled. Motor operation stops when it is disabled. (In OFF mode, all of output MOSFETs are turned off and become the high impedance state.) To prevent the motor from operating outside the VM operating voltage range, following ENABLE pin setting is recommended. Configure ENABLE pin to low level in powering on and shutdown, and switch it to high level after VM voltage is stabilized at the usage voltage. ENABLE High Low Function Motor operation: ON (Normal operation) Motor operation: OFF (Hi-Z) 8.3. CW/CCW function (Output logic at charge start) This function controls the rotation direction of the stepping motor. When CW/CCW pin is set to high level, OUT (+) pin outputs a high level signal and OUT (-) pin outputs a low level signal in the charge starting. When CW/CCW pin is set to low level, OUT (+) pin outputs a low level signal and OUT (-) pin outputs a high level signal in the charge starting. CW/CCW High Low Function Clock-wise: The current of Ach leads the current of Bch by 90-degree phase difference. Counter clock-wise: The current of Bch leads the current of Ach by 90-degree phase difference. 9 / 33

10 8.4. RESET function This function initializes the internal electrical angle. The standby mode can be configured by setting DMODE0, DMODE1, and DMODE2 pins low level. Note: Built-in digital filter of μs (±20 %) is adopted to RESET pin. RESET High Low Function Initializes the internal electrical angle Normal operation When the electrical angle is initialized by setting RESET pin to high level, the relation of the current setting for each H-bridge (Ach and Bch) and the electrical angle is shown below. In the case the MO pin level is pulled up, it shows low level (internal open-drain MOSFET turns on) when the electrical angle is initialized. Step resolution Ach current Bch current Electrical angle 1/32 step setting 71% 71% 45 1/16 step setting 71% 71% 45 1/8 step setting 71% 71% 45 Half (b) step setting 71% 71% 45 Quarter step setting 71% 71% 45 Half (a) step setting 100% 100% 45 Full step setting 100% 100% / 33

11 8.5. MO (Monitor Output: electrical angle output) function MO pin outputs an internal initial electrical angle as a signal. Since MO pin is an open drain type pin, please pull up this pin to the power supply such as VCC to enable this function. (The pull-up resistor value should be set between 10 kω and 100 kω.) MO pin outputs high level with the pulled-up state because it is in high impedance (Hi-Z) state during the normal operation. When the internal electrical angle corresponds to the initial angle, the pin level becomes low (internal open-drain MOSFET turns on) as shown below. In case MO pin is not used, leave the pin open state or connect it to GND. MO High (Hi-Z) Low Function Electrical angle is not at the initial position Electrical angle is at the initial position MO 10 kω to 100 kω VCC If the electrical angle corresponds to the initial angle, the internal MOSFET turns on and the pin voltage level is low. If the electrical angle is not equal to the initial angle, the internal MOSFET turns off and the pin voltage level is high (VCC). Note: The equivalent circuit diagrams may be simplified or some parts of them may be omitted for explanatory purposes Step resolution setting Table 8.1 DMODE function DMODE0 DMODE1 DMODE2 Function Low Low Low Standby mode (Internal oscillator circuit (OSCM) and output MOSFETs turn off.) Low Low High Full step resolution Low High Low Half (a) step resolution Low High High Quarter step resolution High Low Low Half (b) step resolution High Low High 1/8 step resolution High High Low 1/16 step resolution High High High 1/32 step resolution Note: After the standby mode is released, do not input a motor driving signal until the internal circuit becomes stable. (Indication time is 1 ms after the release of the standby mode.) It is recommended to switch the DMODE0, DMODE 1, and DMODE 2 after the RESET signal is set to low level in the initial state (MO = Low). 11 / 33

12 8.6. AGC (Active Gain Control) AGC is an abbreviation for Active Gain Control that is our original driving technology. When required motor torque is lower than the configured constant current value, the motor can drive efficiently by decreasing driving current. When higher torque is required, motor stall can be prevented by increasing the constant current value AGC0 and AGC1 functions AGC0 pin and AGC1 pin switch ON/OFF of the Active Gain Control (AGC). When both pins are set to high level, AGC turns on. The motor current is decreased according to the load torque. Upper current limit is determined by VREF. When pin configuration is (AGC0, AGC1) = (Low, Don t Care), AGC is turned off. The IC can be used as a constant current driver because it operates with the current, which is set by VREF. The difference between the configurations of (AGC0, AGC1) = (Low, Don t Care) and (AGC0, AGC1) = (High, Low) is waveforms in full step resolution. AGC monitors the state of each output pin where the current value continues to be zero, and use this monitoring result for internal signal detection. However, in full step resolution drive, continuous period of zero-level current does not exist in principle. Therefore, the IC generates the judging period by controlling a certain period of zero-level current. This period is automatically generated by the IC, so users do not need to control the period externally. In the case of switching AGC (e.g., fixing AGC0 pin high level and switching AGC1 pin from high to low level.) (Note), zero-level current duration is always provided also in the full step resolution. This reduces the change of current waveforms occurred by turning on or off AGC. On the other hand, in the case that AGC0 pin is set to low level and AGC1 pin is set Don t care, this zero-level current duration is not configured because it is not necessary. In this mode, the IC can be used as a general CLK-In type driver. Built-in digital filter of μs (±20%) is adopted to AGC0 and AGC1 pins. AGC0 AGC1 Mode Function Existence of zero-level current period in full step resolution High High AGC ON mode Anti-stall function (AGC): ON Exist High Low AGC Active OFF mode Anti-stall function (AGC): OFF Exist Low (Don t care) AGC OFF mode Anti-stall function (AGC): OFF No exist Note: Generally, when using this IC, fix the pin configuration in either (AGC0, AGC1) = (High, High) (i.e., AGC ON mode) or (AGC0, AGC1) = (Low, Don't care) (i.e., AGC OFF mode). When it is necessary to switch the anti-stall function (AGC) on or off during motor driving, use the AGC Active OFF mode by switching the AGC1 pin level. Do not switch the AGC0 pin level during motor operation. 12 / 33

13 CLIM (AGC bottom current limit) function AGC judges the required torque value and decreases the current value from the constant current, which is set by VREF. In order to avoid stalls including motor-system stalls, this constant current value should have enough margins. Since actual required current value for motor driving is generally lower than this set current value, the motor driving current is reduced to the minimum required value (torque value) when AGC is enabled. However, in the case that the load torque is very small, the set current itself becomes very small. And when the required torque becomes high due to the load fluctuates, its current difference may be very big. In this case, following problems generate; it takes longer time to increase the current to the required level, and delay of torque following (depending on motor characteristics) occurs stalling. As a counter measure for above problems, CLIM (Current limit) function prevents the current value from falling too much compared to the set constant current value. CLIM0 and CLIM1 pins can set the lower current limit in 8 levels. CLIM0 is a 2 stated logic input, and CLIM1 is a 4 stated logic input. Usually, it is effective to start the evaluation from the Iout 80% condition and lower the current limit to determine the margin limit that allows the system operation. This evaluation can be performed by using CLIM0 and CLIM1 setting combinations. Even when operating the IC with Iout 80% condition, the power consumption can be saved greatly because it is proportional to the square of Iout. Built-in digital filter of μs (±20%) is adopted to CLIM0 and CLIM1 pins. This function is disabled when AGC is not used. CLIM0 CLIM1 Function Connected to VCC AGC bottom current limit: Iout 80% High Pulled up to VCC with100 kω-resistor Pulled down to GND with100 kω-resistor AGC bottom current limit: Iout 75% AGC bottom current limit: Iout 70% Connected to GND AGC bottom current limit: Iout 65% Connected to VCC AGC bottom current limit: Iout 60% Low Pulled up to VCC with100 kω-resistor AGC bottom current limit: Iout 55% Pulled down to GND with100 kω-resistor AGC bottom current limit: Iout 50% Connected to GND AGC bottom current limit: Iout 45% 13 / 33

14 BOOST (current boost) function BOOST pin sets the current boost level (i.e., return to the initial constant current setting value) when the load torque increases. BOOST pin is a 4 stated logic input pin, setting the compensation value in accordance with the existence of the 100 kω-resistor. In the following table, Mode 1 has the fastest current recovery, and Mode 4 has the slowest one. The "step" of the function in the table means the number of divisions of the current change, indicating that the smaller this value is, the faster the current boosts (i.e., recovers). Determination of the mode depends on the load torque change of the used system. For example, in using the system with rapid torque fluctuations, Mode 1 is suitable. In using the system with slow torque fluctuations, Mode 3 or Mode 4 can be adopted. In general, it is recommended to evaluate the operation by using Mode 1 as the standard and shift to Mode 2 and Mode 3 to verify whether the torque-following is possible or not. Built-in digital filter of μs (±20%) is adopted to BOOST pin. Mode BOOST Function Recovery speed 1 Connected to VCC 2 3 Pulled up to VCC with100 kω-resistor Pulled down to GND with100 kω-resistor 4 Connected to GND Takes 5 steps in maximum to reach 100 % current (design value) Takes 7 steps in maximum to reach 100 % current (design value) Takes 9 steps in maximum to reach 100 % current (design value) Takes 11 steps in maximum to reach 100 % current (design value) Fast Slightly fast Slightly slow Slow 14 / 33

15 FLIM (AGC frequency limit) function FLIM pin sets the bottom frequency (frequency limit) for AGC to be active. Since AGC uses an induced voltage in operating, some motors have unstable AGC operation when the motor rotation is very slow. Also, the motor s own resonance frequency influences on the AGC operation. Thereby, the lower frequency limit for AGC activation is necessary to avoid above and can be set by FLIM pin. FLIM pin is a 4 stated logic input. Built-in digital filter of μs (±20%) is adopted to FLIM pin. Mode FLIM Function 1 Connected to VCC Frequency limit: ON, AGC is invalid when fclk is less than 675 Hz 2 3 Pulled up to VCC with100 kω-resistor Pulled down to GND with100 kω-resistor Frequency limit: ON, AGC is invalid when fclk is less than 450 Hz Frequency limit: ON, AGC is invalid when fclk is less than 225 Hz 4 Connected to GND Frequency limit: OFF When connected to GND, the operation is not limited by the limiter circuit of the IC. The induced voltage of the motor, which is used in AGC, is generated by the rotation of the motor. Therefore, the frequency threshold for AGC activation is unique to the motor. The frequency threshold for AGC activation shown in the above table is the case of full step resolution. When using other step resolutions (micro step resolution), the thresholds are different. In micro stepping, the thresholds are roughly equivalent to conversion of the full step resolution. Please refer to the table below. FLIM Full step resolution Half (a) step resolution Half (b) step resolution Quarter step resolution 1/8 step resolution 1/16 step resolution 1/32 step resolution Connected to VCC 675 Hz 1.35 khz 1.35 khz 2.7 khz 5.4 khz 10.8 khz 21.6 khz Pulled up to VCC with100 kω-resistor Pulled down to GND with100 kω-resistor Connected to GND 450 Hz 900 Hz 900 Hz 1.8 khz 3.6 khz 7.2 khz 14.4 khz 225 Hz 450 Hz 450 Hz 900 Hz 1.8 khz 3.6 khz 7.2 khz Frequency limit: OFF LTH (AGC detection threshold) function LTH pin sets AGC detection threshold. Torque detection sensitivity can be set by changing the connected resistor value. When lowering the resistor value, the detection sensitivity increases but the constant current value may become unstable for some motors. Therefore, caution should be exercised. The resistor can be lowered to about 10 k Ω. Connect a 100 kω-resistor in the normal usage. LTH Pulled down with100 kω-resistor Pulled down with10 kω-resistor Function Standard configuration for AGC detection threshold Upper limit configuration for AGC detection threshold 15 / 33

16 9. IC Signal Output Function 9.1. LO1, LO2 (Error Output: Error detect flag output) function LO1 pin and LO2 pin output signals when the error state of the IC or its environment is detected. Both pins are open drain type like MO pin, therefore to use the function properly, they should be pulled up to the power supply (3.3 V/5 V) such as VCC. Use the pull-up resistor in the range of 10 kω to 100 kω. During normal operation, they are high-impedance (Internal open-drain MOSFETs turn off and pin voltage is VCC). Once the error detect function (thermal shutdown (TSD), over current protection (ISD), or motor load open (OPD)) operates, pin voltage becomes low level (Internal open-drain MOSFETs turn ON). When the error detection is released by reasserting the VM power supply or using the standby mode, LO1 pin and LO2 pin show normal operation status again. If this function is not used, leave the pins open or connect them to GND. LO1 LO2 Function High (Hi-Z) High (Hi-Z) Normal state (Normal operation) High (Hi-Z) Low Detects motor load open (OPD) Low High (Hi-Z) Detects over current (ISD) Low Low Detects over thermal (TSD) LO1, LO2 10 kω to 100 kω VCC Once the error detection operates, internal MOSFETs of both or either LO1 or LO2 are turned on. (Pin voltage is low level.) During normal state, internal MOSFETs of both LO1 and LO2 are turned off. (The pin voltage is high level (VCC). Note: The equivalent circuit diagrams may be simplified or omitted for explanatory purposes. 16 / 33

17 10. Application Circuit Example Note: Some of the functional blocks, circuits, or constants in the block diagram may be omitted or simplified for explanatory purposes. Note: Above application circuit example is provided for reference purposes only, and is not guaranteed for mass production. Figure 10.1 Application circuit example 17 / 33

18 11. External Component Description Capacitors for power supply pins To stabilize the power supply voltage of the IC and reduce the noise, connect an appropriate capacitor to each pin. It is effective and recommended to connect capacitors as close to the IC as possible. However, be sure to consider the influence of the IC s heat generation. Also, connecting the small-capacity ceramic capacitor (bypass capacitor) near the IC is effective to reduce power supply fluctuations and noise especially at the high frequency range. Generally, this can be adopted to dealing of CMOS LOGIC IC board. Table 11.1 Recommended capacitor values for power supply pins Item Components Typ. Recommended range Between VM pin and GND Decoupling capacitor (CVM1) 100 μf 22 to 100 μf Between VCC pin and GND Between VREF pin and GND Bypass capacitor (CVCC) 0.1 μf 0.01 to 1 μf Bypass capacitor (CVF) 0.1 μf 0.01 to 1 μf Connect the capacitor in necessary between VREF pin and GND in accordance with the usage environment. It is possible to remove the capacitor and use other than the recommended one depending on the motor load condition and the designed pattern of the board. For example, in case of using two or more motors (the same number of driver ICs as the motors are used), the capacitor between VM pin and GND can be reduced. Comprehensively, ensure the capacitor not to increase the ripple of the power supply. 18 / 33

19 11.2. Internal oscillation frequency OSCM oscillation frequency can be adjusted by changing the constant numbers of external capacitor and resistor. In adjusting, it is recommended to change the resistor, while fixing the capacitor to 270 pf. Chopping frequency can be also changed by adjusting OSCM frequency. Please refer to below table in adjusting the chopping frequency. Product name: Board: Power supply voltage: COSC: TB67S279FTG, TB67S289FTG, and TB67S249FTG Our company s evaluation board 24 V 270 pf Table 11.2 Relation of external resistor (ROSC) and internal oscillation frequency (foscm), chopping frequency (fchop) (for reference only) ROSC foscm fchop kω MHz khz Setting chopping frequency range 40 kω to 150 khz Typical value Note: Values in above table are reference data. They are not guaranteed. 19 / 33

20 Graph of ROSC and foscm (reference data/measurement data example) foscm [MHz] ROSC [kω] Figure 11.1 Graph of ROSC and foscm (reference data/measurement data example) 180 Graph of ROSC and fchop (reference data/measurement data example) fchop [khz] ROSC [kω] Figure 11.2 Graph of ROSC and fchop (reference data/measurement data example) Note: Values in the graphs are reference data. They are not guaranteed. 20 / 33

21 11.3. Resistor for monitor pin The IC has MO, LO1, and LO2 open-drain type pins to output some of the internal status of the IC. When internal open-drain MOSFETs turn off, these pins show high impedance. In using this function, they should be pulled up to the power supply (3.3 V/5 V) such as VCC. If this function is not used, leave the pins open or connect them to GND. Table 11.3 Recommended resistor values for monitor pins Item Components Typ. Recommended range Between (MO/LO1/LO2 pin) and power supply Chip/Lead resistor 10 kω 10 kω to 100 kω Wiring pattern for power supply and GND Since large current is assumed to flow in the pattern connected to VM, OUT, and GND pins in particular, design the appropriate board in order to avoid the influence of wiring impedance. It is very important for surface mounting packages such as QFN type to radiate the heat from the IC back side (the corner pad and the heat sink) to the GND (i.e., heat sink mounting area). So, design the pattern by considering the heat design Fuse Use an appropriate power supply fuse for the power supply line to ensure that a large current does not continuously flow in the case of over current and/or IC failure. The IC will fully break down when used under conditions that exceed its absolute maximum ratings, when the wiring is routed improperly or when an abnormal pulse noise occurs from the wiring or load, causing a large current to continuously flow and the breakdown can lead to smoke or ignition. To minimize the effects of the flow of a large current in the case of breakdown, appropriate settings, such as fuse capacity, fusing time and insertion circuit location, are required. This IC incorporates over current detection circuit (ISD) that turns off the output of the IC when over current is detected in the IC. However, it does not necessarily protect ICs under all circumstances. If the over current detection circuits operate against the over current, clear the over current status immediately. Depending on the method of use and usage conditions, such as exceeding absolute maximum ratings can cause the over current protection circuit to not operate properly or IC breakdown before operation. In addition, depending on the method of use and usage conditions, if over current continues to flow for a long time after operation, the IC may generate heat resulting in breakdown. To avoid above IC destruction and malfunctions caused by noise, the over current detection circuit has a dead band time. So, it is concerned that the over current detection circuit may not operate depending on the output load conditions because of the dead band time. Therefore, in order to avoid continuing this over current state, use the fuse for the power supply line. 21 / 33

22 11.6. Error detection function This IC incorporates a thermal shutdown circuit (TSD) and an over current protection (ISD), which are unique error detections to power ICs, in addition to a general UVLO function. Each function is described below Thermal shutdown circuit (TSD) When the junction temperature of the IC reaches a preset specified value, the internal detection circuit operates to turn off the output block. The dead band time is provided to avoid a false detection, which is caused by switching and so on. While TSD is activated, the operation of the IC is in the standby mode continuously. To release this function, apply the power supply again or configure the standby mode by DMODE0, DMODE, and DMODE pins. TSD function is activated when the IC is overheated irregularly. Therefore, do not use the TSD function often Dead band time of thermal shutdown circuit This IC has a system clock (foscs = 6.4 MHz (typ.)) to count up a dead band time for the error detection. Thermal shutdown circuit can avoid a false detection by configuring the dead band time, which is counted by the system clock. ttsd = 5 μs (typ.) Over current protection (ISD) When the motor output current exceeds a specified value, over current protection circuit, which is implemented in the output block, operates to turn off the output block. The dead band time is provided to avoid a false detection, which is caused by switching and so on. While ISD is activated, the operation of the IC is in the standby mode continuously. To release this function, apply the power supply again or configure the standby mode by DMODE0, DMODE1, and DMODE2 pins Dead band time of over current protection This IC has a system clock (foscs=6.4 MHz (typ.)) to count up the dead band time for the error detection. Over current protection can avoid a false detection by configuring the dead band time, which is counted by the system clock. tisd = 1.25 μs (typ.) 22 / 33

23 12. Power Consumption of the IC Power of the IC is consumed mainly by the transistor of the output block and by the internal circuit, which includes the logic block. P(total) = Power consumption of the IC P(out) = Power consumption of the motor output block (MOSFET) P(bias) = Power consumption of the internal circuit P(total) = P(out) + P(bias) (1) Power consumption of the motor output block The motor output block consumes the power (P (out)) when the motor current flows in the output MOSFET. In case of driving stepping motors, two channels of H-SW (A-ch and B-ch) are controlled in parallel. Therefore, P (out) can be gained from below formula. P(out) = Number of H-SW (= 2ch) Motor current Motor current On resistance ( P = V I = R(on) I(out) 2 ). (1) The power consumption above is gained under the condition that the motor current reaches the configured peak value. Actually, since the IC performs PWM constant current control, the peak current does not flow continuously. Hence, the average motor current is lower than the configured value due to the current ripple (in the constant PWM drive) and the current decay (in switching step resolution). Therefore, the power consumption above is only for reference. Example) When motor current is 1 A, and the operation mode is full step resolution, P(out) = 2 (ch) 1.0 (A) 1.0 (A) 0.41 (Ω) = 0.82 (W) (2) Power consumption of the internal circuit The power for the internal circuit (P(bias)) including the logic block is continuously consumed by applying VM voltage for the motor operation (standby release mode). It is calculated from below formula. P(bias) = Motor power supply voltage Current consumption = VM IM. (2) Example) When motor power supply voltage of 24 V is applied, P(bias) = VM IM3, then 24 (V) 0.006(A) = (W) From above formula, the rough value of this IC power consumption is as follows; P(total) = P(out) + P(bias) = = (W) The power consumption of the standby mode, which reduces bias current of the internal circuit, can be calculated from the formula (2) by substituting IM1 (standby mode) for IM current consumption. P(bias) = 24 (V) (A) = (W) 23 / 33

24 13. Power dissipation Preliminary Relation equation of the ambient temperature (Ta), the junction temperature (Tj), and the heat resistance (Rth(j-a)) between the junction temperature and the ambient temperature is as follows; Tj = Ta + P Rth(j-a) The IC adopts a surface mounting package, QFN48. QFN48 package radiates the heat mainly from the heat sink of the IC back side to the mounting board. So, Rth(j-a) depends on the board design pattern, GND area, etc. Electrode part (corner pad) for disabled pins of QFN package is connected to the heat sink in the IC. Connect this part to the board by soldering because heat can be radiated from the board surface. Example of thermal calculation: If Rth(j-a) is 25 C/W when the IC is mounted on glass-epoxy 4-layer board, the junction temperature at ambient temperature (Ta = 25 C) can be calculated from below formula. Conditions of the power consumption are as the same as the prior section Power Consumption of the IC. Tj = 25 ( C) (W) 25 ( C/W) = 49.1 C Reference) Relation of power dissipation and ambient temperature 6 PD -Ta graph (1) Stand alone (2) Mounting on 4-layer board R th(j-a) = 25 C/W, This value depends on the board design pattern and mounting conditions. Power dissapation PD (W) Topr (2) (1) Ambient temperature Ta ( C) Figure 10.1 Power dissipation Note: Ta, Rth(j-a), and P(total) depend on the environment, in which the board and motor are used. If the ambient temperature is high, the allowable power consumption is reduced accordingly. 24 / 33

25 14. Foot Pattern Example QFN48 foot pattern example (unit: mm) Figure 14.1 QFN48 foot pattern example Note: The data is for reference only and not guaranteed for mass production. In designing the size of mounting board, determine the foot pattern by considering the solder bridge, the solder connecting strength, the pattern accuracy in making board, and the mounting accuracy of the IC board. 25 / 33

26 15. Board dimensions (original board examples of our company) Input/Output DMODE2 DMODE1 DMODE0 VREFA VREFB CW/CCW CLK Apply power supply voltage (VM) ENABLE RESET Short-circuit to SR4 Connect stepping motor MO LO1 LO2 AGC0 AGC1 CLIM0 CLIM1 FLIM BOOST LTH Figure 15.1 Input /Output As for each power supply and control signal, refer to above figure. 26 / 33

27 15.2. Main part Bypass capacitor for VCC Bypass capacitor for VM Decoupling capacitor for VM Resistor and capacitor for OSCM Pull up resistor for MO Pull up resistor for LO1 Pull up resistor for LO2 Resistor for CLIM1 adjustment Resistor for FLIM adjustment Resistor for BOOST adjustment Resistor for LTH adjustment Figure 15.2 Main part Connect each external components referring to 10. Application Circuit Example. 27 / 33

28 15.3. Options When VCC is used as the switch for high level or as the connecting point for pulled up resistor, short-circuit SR3. In this case, do not apply voltage to VDD pin. Use it when VREF is applied by dividing resistive voltage of VCC. (Refer to the following section of SVF pin.) When VREFA and VREFB are applied as common power supply, short-circuit SR5. In this case, apply the voltage to only one of them, VREFA or VREFB. When VDD (external power supply) is used as the switch for high level or as the connecting point for pulled up resistor, apply 3.3 V or 5 V to VDD pin. In this case, do not short-circuit SR3. Figure 15.3 Options 28 / 33

29 15.4. Board circuit diagram Figure 15.4 Board circuit diagram 29 / 33

30 15.5. SVF pin The motor current and the torque can be changed during operation by using our optional pattern on the board. (Please refer to below circuit diagram.) The applied voltage for VREF can be adjusted by switching the voltage-dividing ratio with the transistor. Use an appropriate resistor for the SVF input (i.e., the base of the transistor) in accordance with the capability of the transistor. VCC RVF1 VREFB VREFB SR5 VREFA CVF RVF2 RVF3 TVF SVF VREFA Figure 15.5 Circuit diagram of SVF pin Note: Total value of the resistance, which is connected between VCC and GND, should be 10 kω to 50 kω regardless of the transistor s switching state. TVF recommended resistor: NPN transistor RN1401 of our company 30 / 33

31 Notes on Contents 1. Block Diagrams Some of the functional blocks, circuits, or constants in the block diagram may be omitted or simplified for explanatory purposes. 2. Equivalent Circuits The equivalent circuit diagrams may be simplified or some parts of them may be omitted for explanatory purposes. 3. Timing Charts Timing charts may be simplified for explanatory purposes. 4. Application Circuits The application circuits shown in this document are provided for reference purposes only. Thorough evaluation is required, especially at the mass production design stage. Any license to any industrial property rights is not granted by provision of these application circuit examples. 5. Test Circuits Components in the test circuits are used only to obtain and confirm the device characteristics. These components and circuits are not guaranteed to prevent malfunction or failure from occurring in the application equipment. IC Usage Considerations Notes on handling of ICs (1) The absolute maximum ratings of a semiconductor device are a set of ratings that must not be exceeded, even for a moment. Do not exceed any of these ratings. Exceeding the rating(s) may cause the device breakdown, damage or deterioration, and may result injury by explosion or combustion. (2) Use an appropriate power supply fuse to ensure that a large current does not continuously flow in the case of over current and/or IC failure. The IC will fully break down when used under conditions that exceed its absolute maximum ratings, when the wiring is routed improperly or when an abnormal pulse noise occurs from the wiring or load, causing a large current to continuously flow and the breakdown can lead to smoke or ignition. To minimize the effects of the flow of a large current in the case of breakdown, appropriate settings, such as fuse capacity, fusing time and insertion circuit location, are required. (3) If your design includes an inductive load such as a motor coil, incorporate a protection circuit into the design to prevent device malfunction or breakdown caused by the current resulting from the inrush current at power ON or the negative current resulting from the back electromotive force at power OFF. IC breakdown may cause injury, smoke or ignition. Use a stable power supply with ICs with built-in protection functions. If the power supply is unstable, the protection function may not operate, causing IC breakdown. IC breakdown may cause injury, smoke or ignition. (4) Do not insert devices in the wrong orientation or incorrectly. Make sure that the positive and negative pins of power supplies are connected properly. Otherwise, the current or power consumption may exceed the absolute maximum rating, and exceeding the rating(s) may cause the device breakdown, damage or deterioration, and may result in injury by explosion or combustion. In addition, do not use any device inserted in the wrong orientation or incorrectly to which current is applied even just once. 31 / 33

32 (5) Carefully select external components (such as inputs and negative feedback capacitors) and load components (such as speakers), for example, power amp and regulator. If there is a large amount of leakage current such as from input or negative feedback condenser, the IC output DC voltage will increase. If this output voltage is connected to a speaker with low input withstand voltage, over current or IC failure may cause smoke or ignition. (The over current may cause smoke or ignition from the IC itself.) In particular, please pay attention when using a Bridge Tied Load (BTL) connection type IC that inputs output DC voltage to a speaker directly. Points to remember on handling of ICs (1) Over current protection Circuit Over current protection circuits (referred to as current limiter circuits) do not necessarily protect ICs under all circumstances. If the over current protection circuits operate against the over current, clear the over current status immediately. Depending on the method of use and usage conditions, exceeding absolute maximum ratings may cause the over current protection circuit to operate improperly or IC breakdown may occur before operation. In addition, depending on the method of use and usage conditions, if over current continues to flow for a long time after operation, the IC may generate heat resulting in breakdown. (2) Thermal Shutdown Circuit Thermal shutdown circuits do not necessarily protect ICs under all circumstances. If the thermal shutdown circuits operate against the over temperature, clear the heat generation status immediately. Depending on the method of use and usage conditions, exceeding absolute maximum ratings may cause the thermal shutdown circuit to operate improperly or IC breakdown to occur before operation. (3) Heat Radiation Design When using an IC with large current flow such as power amp, regulator or driver, design the device so that heat is appropriately radiated, in order not to exceed the specified junction temperature (Tj) at any time or under any condition. These ICs generate heat even during normal use. An inadequate IC heat radiation design can lead to decrease in IC life, deterioration of IC characteristics or IC breakdown. In addition, when designing the device, take into consideration the effect of IC heat radiation with peripheral components. (4) Back-EMF When a motor rotates in the reverse direction, stops or slows abruptly, current flows back to the motor s power supply owing to the effect of back-emf. If the current sink capability of the power supply is small, the device s motor power supply and output pins might be exposed to conditions beyond the absolute maximum ratings. To avoid this problem, take the effect of back-emf into consideration in system design. 32 / 33

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Please use Product in compliance with all applicable laws and regulations that regulate the inclusion or use of controlled substances, including without limitation, the EU RoHS Directive. TOSHIBA ASSUMES NO LIABILITY FOR DAMAGES OR LOSSES OCCURRING AS A RESULT OF NONCOMPLIANCE WITH APPLICABLE LAWS AND REGULATIONS. 33 / 33